Spring 2010 International NORTH AMERICAN LIMOUSIN FOUNDATION. Limousin Genetic Evaluation

Transcription

1 Spring 2010 International NORTH AMERICAN LIMOUSIN FOUNDATION Limousin Genetic Evaluation

2 Understanding EPDs and Accuracies Expected Progeny Differences (EPDs) Expected Progeny Differences (EPDs) are used to compare the genetic merit of animals in various traits. An EPD predicts the difference in performance of future offspring of a parent, as compared to progeny from other parents, when each are bred to mates of equal value. Remember, the observed performance of an animal is determined by both genetics and environment, and EPDs only predict differences due to genes passed on from parent to offspring. Another fundamental concept of interpreting EPDs is to recognize that EPDs serve to rank animals. By comparing an animal s EPD for a given trait to the average EPD of all animals, one can determine if the animal is above or below average. Further, by familiarizing yourself with the percentile ranking table, you can determine the degree to which an animal is above or below average for a given trait. Calving Ease Direct and Maternal EPDs The Limousin breed has an excellent reputation for calving ease and associated calf vigor and survivability. But even low levels of calving difficulty can mean increased veterinary and labor costs, calf death loss, calf susceptibility to disease, cow mortality, delayed return to estrus and lower conception rates. While birth weight EPDs are useful indicators of potential calving ease, NALF s EPDs for calving ease direct and maternal can help users of Limousin genetics more effectively select for higher levels of calving ease in replacement heifers. Higher calving ease EPDs are favored and indicate genetics for greater chances of unassisted births in first-calf heifers. The calving ease direct (CED) EPD is important for choosing which sires to breed to firstcalf heifers to produce calves that are born easily. The calving ease maternal (CEM) EPD is important for choosing sires that produce replacement heifers that give birth to their first calf easily. Consider the following two sires for use on firstcalf replacement heifers and their CED EPDs: CED EPD Sire A +5% Sire B 5% Difference 10% When sires A and B are bred to similar replacement heifers, you d expect 10 percent (the difference between +5% and 5%) more of sire A s calves to be born unassisted as compared to sire B s calves. Said another way, due to genes for calving ease passed on from the sires to their calves, each of sire A s calves out of first-calf heifers have a 10 percent greater chance of being born unassisted as compared to sire B s calves. Next, let s briefly look at the following two sires from which replacement heifers are to be retained and what we d expect based on their CEM EPDs: CEM EPD Sire A +3% Sire B 2% Difference 5% When daughters of sires A and B are bred to similar bulls, daughters of sire A have a 5 percent greater chance of calving unassisted with their first calf as compared to daughters of sire B, due to differences in genes the daughters inherited from their sires for easy delivery of their first calves NALF North American Limousin Foundation 7383 S. Alton Way, Suite 100 Centennial, CO / FAX 303/ Canadian Limousin Association #13, th St. NE Calgary, Alberta, Canada T2E 7C4 403/ FAX 403/

3 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 2 Birth Weight EPDs Birth weight has been identified as the single most influential factor contributing to calving difficulty. In studies of birth weight data, birth weight EPDs have been shown to be the single most accurate genetic predictor of calf birth weight. In order to demonstrate how birth weight EPDs work, consider the following two bulls that are being considered for use on first-calf heifers, and the difference between their birth EPDs. Birth Wt. EPD Bull A -2.5 lbs. Bull B +2.5 lbs. Difference 5.0 lbs. If bulls A and B were each bred to a similar set of heifers, based on their EPDs we would expect calves from bull A to have birth weights that average 5 lbs. less than calves from bull B. Lower birth weight EPDs indicate lighter progeny birth weights, which generally should translate into less potential for calving difficulty. Weaning and Yearling Weight EPDs Feeder cattle are marketed by the pound. Typically, heavier calves return more total dollars than lighter weight calves, assuming you have just as many heavy calves as light calves to offer for sale. Weaning and yearling weight EPDs are expressed as the added pounds of weaning and yearling weight of offspring expected, due to genes for growth passed on from parents. As an example, consider the weaning and yearling EPDs on the following two bulls: Weaning Wt. Yearling Wt. EPD EPD Bull A 45 lbs. 85 lbs. Bull B 35 lbs. 65 lbs. Difference 10 lbs. 20 lbs. In this example, bull A is expected to pass on genes to his calves which result in weights that average 10 lbs. more at weaning and 20 lbs. more at yearling as compared to the average of calves sired by bull B. Here, the weaning weight difference of calves is solely due to genes for growth the calves inherited from each sire, and is separate from the influence that the dam s milking ability has on calf weaning weight. Milking Ability EPDs Milk EPDs are more difficult to explain. Read carefully...a sire s milk EPD is expressed as the additional pounds of weaning weight of calves (grandprogeny of sire) from daughters, due to genes for milk passed on from the sire to his daughters. Similarly, a dam s milk EPD indicates added pounds of weaning weight of calves (grandprogeny of dam), from her daughters, due to genes for milk the daughters inherited from the dam. An example helps make milk EPDs easier to understand. Consider the following two bulls: Milk EPD Bull A 20 lbs. Bull B 10 lbs. Difference 10 lbs. Again, EPDs are used to make comparisons. The difference in milk EPD of bulls A and B is 10 lbs. Daughters of bull A are expected to wean calves that are 10 lbs. heavier than the calves from daughters of bull B, due to genes for milking ability the daughters inherited from sires A and B. Determining the optimum range in milk EPDs which is most appropriate for any given situation and the amount of emphasis that should be given to this trait depends upon a number of different factors, including environment and management practices. Scrotal Circumference EPDs Older age at puberty has been linked to lower conception rates and later calving dates in females, a reduction in the quality and quantity of semen produced by bulls, and poor performance in several other measures of reproduction and fertility. Thus, it is important for Limousin breeders to correct potential deficiencies in this trait, especially if replacement females are retained for breeding from the bulls in question. Scrotal circumference has been found to be a good indicator of age at puberty, and is a highly heritable trait which responds favorably to selection. EPDs for scrotal circumference are expressed in centimeters

4 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 3 (cm), with higher values indicating genes for larger yearling scrotal circumferences of sons and earlier puberty of daughters. Consider the scrotal EPDs for the following two bulls: Scrotal Circumference EPD Bull A.5 cm Bull B +.5 cm Difference 1.0 cm If bulls A and B were each bred to a similar set of cows, we would expect bull calves from sire B to have yearling scrotal circumferences which average 1.0 cm larger than bull calves from sire A at 12 months of age. Since yearling scrotal circumference in bulls and age at first cycling (puberty) in heifers are highly correlated traits, daughters of bull B would also be expected to have inherited genes for earlier puberty than daughters of bull A. It is important to consider scrotal circumference EPDs when selecting bulls from which daughters are going to be retained for replacements. Also note that scrotal circumference EPDs are not substitutes for breeding soundness examinations (BSEs) conducted by veterinarians. Breeders are advised to use scrotal EPDs to determine genetic differences in puberty and utilize results from BSEs (includes evaluation of semen, actual scrotal circumference measurements and physical examinations) to help identify infertile or subfertile bulls. Use of the BSE should be a routine practice prior to merchandising and prior to the start of each breeding season. Please contact the NALF office for additional information on BSEs. Stayability EPDs Stayability EPDs are calculated from calving and pedigree information, and predict genetic differences in the likelihood that daughters will remain in production until six years of age or beyond, given that daughters had at least one calf reported prior to six years of age. Since the primary reason Limousin cows are culled is because of reproductive failure, EPDs for stayability are mainly thought to indicate genetic differences in sustained reproduction. To a lesser extent, stayability EPDs may also represent genetic differences in a multitude of additional factors which contribute to reasons why daughters of certain sires are preferred by Limousin breeders, and as a result have calves reported before and after six years of age. The following example using two sires illustrates how to interpret stayability EPDs. Stayability EPD Bull A + 25% Bull B + 15% Difference 10% If sires A and B above were bred to comparable groups of cows, 10% more of sire A s daughters are expected to remain in production until the age of six years as compared to sire B s daughters (+25% 15% = 10%). Said another way, each daughter of sire A is expected to have a 10% greater likelihood of staying in production to six years as compared to daughters of sire B. Stayability EPDs for cows are defined in exactly the same manner, with differences in EPDs indicating differences in the probability that daughters of the cows will remain in production to six years of age. Docility EPDs EPDs for docility predict genetic differences in the probability that offspring are scored as 1 (docile) or 2 (restless) as opposed to 3, 4, 5 or 6 (nervous to very aggressive). Higher EPD values for docility represent genetics for calmer behavior. An example using the following two sires helps make docility EPDs easier to understand and use: Docility EPD Sire A + 20% Sire B + 5% Difference 15% If sire A has a docility EPD of +20% and sire B is +5%, we would expect 15% more of sire A s offspring (20% - 5% = 15%) to be scored as either 1 (docile) or 2 (restless) as compared to the percent of offspring of sire B scored as 1 or 2. By definition, each offspring of sire A is expected to have a 15% greater likelihood of possessing docility scores of 1 or 2 as compared to offspring of sire B. Thus, docility EPDs can be used to minimize the proportion of animals produced and perhaps culled which possess genetics for potentially unacceptable behavior.

5 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 4 Carcass Weight EPDs Carcass weight EPDs are tools to help genetically design carcasses with weights which fall within an acceptable industry weight range. As a means of demonstrating how carcass weight EPDs work, consider the following two bulls: Carcass Wt. EPD Bull A + 10 lbs. Bull B + 40 lbs. Difference 30 lbs. If bulls A and B were each bred to comparable groups of cows, the average carcass weights of the resulting offspring of each sire would differ by 30 lbs. due to genes for carcass weight from the sires. More specifically, on average, offspring of bull B would produce carcasses which are 30 lbs. heavier than carcasses from bull A, at an age constant end point. Knowing which of the above two bulls is most appropriate is a difficult question. On one hand, bull B is expected to produce more total carcass weight. However, if bull B produces some carcasses which are too heavy, overweight discounts may work to bull B s disadvantage. Optimum carcass weight EPDs for sires will vary according to characteristics of the cows to which the sires are mated and the calf growing/finishing management regime. Gaining a feel for optimum carcass weight EPDs will require some trial and error until thresholds are more clearly defined. In the meantime, avoiding extremes on both ends of the carcass weight EPD spectrum may be a logical alternative. It follows that selecting sires of moderate size will help avoid production of carcass weights which are outside of an acceptable weight range. Ribeye Area EPDs Ribeye area EPDs offer an objective measurement of genetic differences in muscularity. EPDs for ribeye area are expressed in units of square inches, with larger values indicating larger ribeye areas and increased expected overall carcass muscularity. As an example of how to interpret ribeye area EPDs, consider the following two sires: Ribeye Area EPD Sire A.40 sq. in. Sire B +.60 sq. in. Difference 1.00 sq. in. By definition, if sires A and B are mated to similar groups of cows, the average ribeye area of calves from sire B are expected to be 1.00 square inch larger than the average of calves from sire A at an age constant end point, due to genes passed on for ribeye area. Similar to carcass weight, bigger is not necessarily better. The challenge to cattle producers appears to be one of producing muscular, high red meat yield type finished cattle without overstepping thresholds on carcass and ribeye size. Yield Grade EPDs USDA yield grades estimate beef carcass cutability, which is defined as the combined yield of closely trimmed, boneless retail cuts from the round, loin, rib and chuck. Yield grades range from 1 to 5, with lower values being more favorable and indicating greater yield of lean, saleable beef from the carcass. Just as lower yield grade EPDs are favored and indicate greater cutability, lower yield grade EPDs are favored and indicate genetic differences for yield grade and cutability of offspring. Generally, animals with the most favorable combination of EPDs for large ribeye area, low fat thickness and light carcass weight also have the most desirable and lowest EPDs for yield grade. To get a feel for interpreting EPDs for yield grade, consider sires A and B listed below: Yield Grade EPD Sire A.25 Sire B +.25 Difference.50 When bred to similar cows, offspring of sire A are expected to average one-half (.50 units) of a yield grade better than offspring of sire B. This is expected to equate to a little over one percent (1.15%) greater yield of closely trimmed, boneless retail product from carcasses of sire A s offspring compared to sire B s. Assuming 800 pound carcass weights, carcasses from progeny of sire A are expected to yield an average of slightly over 9 pounds (1.15% x 800 lbs. = 9.2 lbs.) more retail product than carcasses from progeny of sire B.

6 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 5 Marbling Score EPDs Marbling scores are subjective evaluations of intramuscular fat in the ribeye. The marbling score EPD is expressed in units of numeric marbling score, with higher values indicating genes for greater deposition of intramuscular fat, or higher expected marbling score and higher USDA quality grade at a constant age. Consider the marbling score EPDs of sires A and B for an illustration of how to interpret these values: Marbling Score EPD Sire A.25 Sire B +.25 Difference.50 If bred to comparable groups of cows and processed at a constant age, the average marbling score of carcasses from offspring of sire B is expected to be.50 score units higher than the average of carcasses of offspring produced by sire A, due to genes passed on from the sires for marbling score. Generally, higher marbling score EPDs are favored over lower values. Choice grade carcasses are typically more valuable than carcasses which grade Select or lower, if other carcass characteristics are equal. This is because of the anticipated benefits to juiciness and flavor which higher marbling scores are expected to help ensure. When deciding how much emphasis to place on this trait, it should be remembered that a number of additional factors such as age, days on feed, post-mortum treatments and cooking can have substantial influence on palatability. Also, tenderness has been shown to be the most important component of overall palatability, and it has been demonstrated that there is not a meaningful relationship between level of marbling and tenderness in Limousin cattle. Mainstream Terminal Index The mainstream terminal index ($MTI) is a multiple-trait selection index, expressed in dollars per head, designed to assist beef producers by adding simplicity to genetic selection decisions. It measures differences in expected profit per carcass produced on a mainstream grid (yield grade 1 or 2, Select to low-choice quality grade, and no over- or underweights or dark cutters). The $MTI is based on the assumption that Angus- Hereford cows in a two-breed rotation are mated to Limousin-influenced terminal sires with the resulting calves sold into the commodity beef market with premiums and discounts based on both quality and yield. It is determined by economic values and genetics associated with post-weaning growth, yield grade and quality grade and gives an estimate of how future progeny of each sire are expected to perform, on average, compared to progeny of other sires in the Limousin herdbook if the sires were randomly mated to similar herds of black baldy cows and if the calves were exposed to the same environment. For example, a bull with a +$55 for $MTI would be expected to return $15 more per carcass produced than a bull with a +$40 for $MTI ($55 - $40 = $15) due to combined genetic merit for post-weaning growth and mainstream carcass merit passed on to offspring. If each bull produced 25 carcasses per year over the next four years, the +$55 bull would be expected to produce an extra $2,500 return over the +$40 bull: ($55 $40) x 25 carcasses per year x 4 years of service = $2,500 When using $MTI, it is wise to simultaneously select for economically important traits that are not included in the index. The index was developed for use in a terminal sire situation in which Limousin and Lim-Flex bulls are bred to mature British-cross cows and all calves are placed in the feedlot and sold on a mainstream grid. Maternal traits, such as calving ease, are not included in the index. If you intend to use high $MTI bulls on first-calf heifers, you will also want to use EPDs for calving ease direct to minimize calving difficulty. Likewise, in order to keep pace with the Limousin breed s tremendous improvement in temperament, selection for superior docility EPDs is also advised. It is also important to understand the assumptions behind $MTI and consider genetic differences among animals in the component traits that contribute to $MTI. For example, a $45 bull whose $MTI value comes from superiority in marbling is a more appropriate choice than a $45 bull whose value is from high growth and low yield when the cows to which they are to be mated are of low genetic merit for marbling. Because $MTI is composed of EPDs for several traits, it does not have an associated value for accuracy. However, animals with high accuracy values for

7 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 6 Table 1. Limousin Possible Change Values (+ or ) for EPDs of Various Traits BIF CE Birth Weaning Yearling Milk CE Scrotal Stayability Docility Carcass Ribeye Marbling Accuracy Direct Wt. Wt. Wt. Maternal Weight Area Score (%) (lbs.) (lbs.) (lbs.) (lbs.) (%) (cm) (%) (%) (lbs.) (in 2 ) (units) each of the component traits (weaning weight, yearling weight, yield grade and marbling score) have more reliable $MTI that are less subject to change than animals with low accuracies for each of the component traits. Accuracy Accuracy is a measure of the reliability associated with an EPD. For Limousin cattle, accuracy is designated by either a P, P+ or a numeric value which ranges from 0 to 1. Accuracy indicates the type and amount of performance information which was used to calculate the EPD. More specifically, EPDs with P accuracy generally have the lowest level of reliability because only pedigree ( P ) information has been included in the calculations. Since an animal inherits a sample half of its genes from each parent, EPDs with P accuracy are calculated by adding 1/2 of the sire s EPD for a given trait to 1/2 of the dam s EPD. Breeders should also consider an animal s adjusted weights and ratios if the EPD only has P accuracy. Accuracy defined as P+ indicates that both pedigree ( P ) data and an animal s own performance and contemporary group information have been incorporated into the animal s EPD. However, the animal s performance and contemporary group information do not contribute back to its parents values until the next genetic evaluation. Also in the next evaluation, an animal s P+ accuracy will be updated to a numeric value. Animals with numeric accuracy have had their own performance and group information and that of their progeny processed through genetic evaluations at the University of Georgia and Colorado State University. Higher accuracy values, those closer to one, indicate greater reliability because more information has been incorporated. The concept of accuracy is more useful if you realize that more data means higher accuracy, and higher accuracy means less error associated with the EPD. Less error means that the EPD is less subject to possible change as more data accumulates. Keep This In Mind Possible change corresponds to accuracy and is a measure of potential error associated with EPDs. It is expressed as the plus (+) or minus ( ) value an EPD may deviate from the animal s true genetic value (Table 1). For a given accuracy, the true progeny differences of 2/3 of all animals evaluated are expected to fall within the plus (+) or ( ) possible change value. Approximately 1/3 of the animals evaluated may have true values outside the range indicated by the possible change. For any range of possible change, the true progeny difference is much more likely to be toward the center of the range than the outside. As more information accumulates, accuracy increases while error or possible change diminishes. For a given trait, possible change values apply to any EPD with that accuracy. Hence, positive EPDs are just

8 U n d e r s t a n d i n g E P D s a n d A c c u r a c i e s 7 as likely to include error as negative EPDs. Table 1 provides possible change values associated with various levels of accuracy. For example, consider the possible change of plus or minus (±) 1.4 lbs. for a milk EPD with a.90 accuracy. A bull with a milk EPD of +20 (.90 accuracy) has about a 1 in 6 chance of having a true milk progeny difference that is 18.6 ( = 18.6) or less and a similar chance of being greater than ( = 21.4). Using this example, two out of three bulls with milk EPDs of +20 and.90 accuracy are expected to have true progeny differences between and (20 ± 1.4). Example: Trait = Milking Ability Milking Ability EPD = +20 Accuracy =.90 Possible Change = ±1.4 Calculations: = = * 2/3 of all animals with the above EPD and accuracy expected to have true progeny differences between and /6 may have true progeny differences less than /6 may have true progeny differences greater than Other Risk Management Information Along with accuracy values for each trait, additional information which helps evaluate the reliability of the EPDs is also provided. The number of contemporary groups from which birth weight records were collected is printed below the birth weight EPD accuracy. This information can be used as an indicator of the extent to which a bull has been sampled in different herds. For milk and scrotal EPDs, the number of progeny weaning weight records from daughters and number of sons with scrotal records, respectively, are also provided to help further measure the reliability of these EPDs. Remember, EPDs can be directly compared regardless of accuracy because the number of records is accounted for in the calculations. Use EPDs to determine which bulls to sample and accuracies to determine how extensively each bull is to be used, relative to the amount of risk you are willing to accept.

9 Guide to Commercial Bull Selection by Lauren Hyde, Ph.D. NALF Director of Performance Programs and Kent Andersen, Ph.D. Former NALF Executive Vice President Now that you ve decided to breed your cows to a Limousin or Lim-Flex bull, it s time to select one. Selecting a herd sire is one of the most important decisions a cow-calf producer makes. A herd bull contributes half of the genes to the calf crop and plays an essential role in the herd s genetic improvement. While a female usually produces only one calf per year, a herd bull may sire 25 or more contributing more to the genetic makeup of the herd in one breeding season than a cow contributes during her entire lifetime Bull selection starts with choosing a reputable breeder. NALF s online member directory at is a good place to start. NALF can also provide you with a list of Limousin breeders in your area. Once you contact a breeder, you may want to find out what type of customer service programs he or she offers such as breeding guarantees, calf buy-backs, delivery and advice in selection as well as management and marketing. Assessing Soundness After you find a breeder and have some bull prospects in mind, assess whether the bull is reproductively and structurally sound. The best way to assess reproductive soundness is through a breeding soundness exam (BSE). A BSE is performed by a veterinarian and consists of a physical exam, a scrotal circumference measurement and a semen evaluation. NALF recommends that bulls should have passed a BSE prior to sale or purchase. The seller should make the results of the BSE available as well as specify the guarantee of the bull s reproductive soundness and fertility. Structural soundness is important in beef sire selection to ensure that a herd sire is capable of effectively breeding females. A breeding bull will need sound feet, legs and eyes in order to seek out females in heat and service them. The bull should have appropriate angles at all weight-bearing joints and move without pain and discomfort. Other factors to consider in your purchase decision include the bull s conformation, body capacity, frame size, muscling/thickness, libido, disposition, color and presence or absence of horns. You may also want to limit your selection to a virgin bull to reduce the risk of any sexually transmitted diseases from occurring in your herd. Understanding EPDs and Accuracies Because a herd bull is responsible for 50 percent of the genes in the resulting calf crop, it is imperative to evaluate the performance characteristics of prospective sires. Selection among bulls for performance should be based on expected progeny differences (EPDs) whenever possible. EPDs provide predictions of the difference in the expected performance of calves sired by one bull compared to calves sired by another bull. EPDs are based on pedigree information and the performance records of animals and their contemporaries, relatives and progeny. EPDs are much better indicators of a bull s genetic worth than actual and adjusted measurements and ratios. Although adjusted measurements and ratios are helpful when making comparisons between bulls from the same contemporary group, they can be misleading when they are used to compare bulls from different groups or even herds. Environmental factors like feed availability and weather conditions can affect an animal s performance. EPDs take environmental effects like these into account, so they can be used to 2010 NALF North American Limousin Foundation 7383 S. Alton Way, Suite 100 Centennial, CO / FAX 303/ Canadian Limousin Association #13, th St. NE Calgary, Alberta, Canada T2E 7C4 403/ FAX 403/

10 G u i d e t o C o m m e r c i a l B u l l S e l e c t i o n 2 Selecting for Profit the UltraMate Way Genetic selection targeting specific carcass endpoints doesn t have to be complicated. The UltraMate Crossbreeding System provides a simple three-step plan to efficiently hit end-product and maternal profit targets. 1. Scope out your cows. Determine the breed composition of your cow herd. How many of your cows are: British and British-cross British-Continental cross Continental Brahman cross 2. Determine your target market. Mainstream Yield grade 1s and 2s Low choice and select Zero misfires Muscle 100% yield grade 1s and 2s Tender and low fat Zero misfires Marbling Mid-choice and higher Yield grade 1s, 2s and 3s Zero misfires 3. Select your genetic solution. Limousin and the Lim-Flex line of Limousin-Angus hybrids provide you with a full seedstock range to hit your carcass and maternal targets. Depending on your cow herd and your market, choose either Limousin or Lim-Flex bulls to put your next calf crop in the profit zone. The table below can help with your decision. Breed Composition Limousin or of Cows Target Market Lim-Flex Bulls? British and British cross Mainstream Limousin Marbling Lim-Flex British-Continental cross Muscle Limousin Mainstream Lim-Flex Marbling Lim-Flex Continental Muscle Limousin Mainstream Lim-Flex Brahman cross Muscle Limousin Mainstream Lim-Flex Once you ve decided on Limousin or Lim-Flex, select sires with the best combination of EPDs and ultrasound scans for your market. Trait Mainstream Muscle Marbling EPDs Growth X X X Ribeye Area X X Yield Grade X X Marbling X X Ultrasound Scans Ribeye Area X X IMF (Marbling) X X fairly compare the genetic merit of animals not only across contemporary groups and herds but also across an entire breed. EPDs are used to make genetic improvement in both seedstock and commercial herds. Genetic improvement can mean higher calf sale weights, enhanced female reproductive function and better performance on the rail all of which can enhance the profitability and viability of the operation. NALF publishes EPDs for 14 economically important traits in its summer and fall sire summaries, along with tables of EPD breed averages and percentile rankings. NALF s web site also has tools that allow producers to look up EPDs for individual animals and to search for sire prospects based on the producer s own EPD selection criteria. EPDs can change over time as additional performance information is collected. Accuracy values are published with EPDs to give an indication of the reliability of the EPDs. Accuracies range from 0 to 1 with values closer to 1 meaning greater reliability. As more performance information becomes available on an animal, the more accurate its EPDs become. Because most bulls purchased by commercial producers are young with few progeny, if any, their EPDs are usually associated with low accuracy values. However, EPDs with low accuracy are still better predictors of genetic potential than either adjusted measurements or ratios. What s more, the accuracies associated with the average EPDs of the sires in the entire bull battery can be quite high. Suppose you are using three bulls with the following yearling weight EPDs and accuracies: Yearling Weight EPD Yearling Weight Accuracy Bull Bull Bull Average Although the accuracy of each bull s yearling weight EPD is only.30, it can be shown mathematically that the accuracy of their average EPD (+85 pounds) is approximately.60. As the number of bulls increases, the accuracy associated with their average EPD for any given trait also increases. Before you can put EPDs to work for you, realize that as you make progress in one trait, you can lose ground in another. This is because of a phenomenon

11 G u i d e t o C o m m e r c i a l B u l l S e l e c t i o n 3 EPD Target Profiles for Bulls in Different Production Scenarios (based on the Spring 2010 International Limousin Sire Summary percentile rankings for born calves) EPD Heifer Bull All-purpose Maternal Bull Carcass/Terminal Bull Percentile EPD Percentile EPD Percentile EPD Calving Ease Direct 10% 13 60% 6 80% 5 Birth Weight 20% % % 3.0 Weaning Weight 60% 41 50% 42 30% 47 Yearling Weight 60% 76 50% 80 30% 87 Milking Ability * * 30% 24 ** ** Calving Ease Maternal 50% 3 40% 4 ** ** Scrotal Circumference 50% % % 0.2 Stayability 60% 16 40% 18 ** ** Docility 40% 17 30% 19 60% 13 Carcass Weight 80% 9 60% 16 30% 27 Ribeye Area 70% % % 0.55 Yield Grade 70% % % 0.11 Marbling Score 60% % % *** 0.09 Mainstream Terminal Index 60% 43 50% 44 30% *** 46 * Match milk to available resources. ** Not applicable if daughters are not retained. *** For mainstream and marbling markets. Not applicable to muscle markets. called pleitropy, where one or more genes affect either negatively or positively more than one trait. A classic example of pleitropy occurs with growth traits. As producers select for increased weaning and yearling weights, birth weights also increase, leading to more dystocia. As well, the mature size of retained replacements can increase causing higher maintenance costs and decreased reproductive function. Using tools like NALF s online sire selector, you can identify animals with favorable EPDs across all antagonisticallyrelated traits. Matching the Bull to the Production Environment Bull selection for any cow herd should target an acceptable combination of traits that complements the strengths and weaknesses of the cow herd. You should try to strike a balance among the various traits and avoid extremes. Bulls should match the cows, markets, management and environment of the operation. To get a clearer picture of the type of bull that s appropriate for your needs, develop goals for your operation and evaluate your herd critically to determine if it will help you meet them. Be prepared to ask yourself some questions: Have you been having problems during calving season? Limit your search to calving ease bulls. Are calf weaning weights lower than you d like? Then choose a bull superior in growth traits. Ultimately, based on the strengths and weaknesses of your cows and the goals for your next calf crop, you ll want to determine a target EPD profile for prospective purchases. NALF s table of EPD percentile breakdowns, published with every sire summary, shows you how animals rank within the breed. The table of percentile rankings can be very helpful in setting minimum or maximum standards for each trait of interest. The following provides EPD selection guidelines for different types of bulls needed for some of the more common production scenarios. Target EPD profiles are given in the accompanying table. The Heifer Bull Use when breeding first-calf heifers. Select a bull with high EPDs for calving ease direct. Because birth weight is a component of calving ease, there is little reason to also select for low birth weight. Extreme selection on both calving ease and birth weight EPDs may result in too much selection emphasis on birth weight and in turn sacrifice growth. The All-purpose Maternal Bull Use when retaining females as replacements and marketing feeder calves. Not only should this bull enhance early puberty and longevity in replacements and keep the mature size and milking ability of the cow herd at moderate levels, but also he should produce superior feeder calves. Select bulls with moderate EPDs for growth and milk. Avoid extremes for these traits. Milk EPDs should be matched to the available forage and feed resources. Consider high scrotal

12 G u i d e t o C o m m e r c i a l B u l l S e l e c t i o n 4 circumference and calving ease maternal EPDs to reduce age at puberty and the incidence of dystocia among daughters. Above average stayability EPDs can enhance longevity and sustained reproductive function among the cows. If temperament is a problem within the herd, look for bulls with high docility EPDs. The Carcass Bull Use when retaining ownership of calves through the feedlot. The purpose of this bull is to produce calves with superior carcass characteristics for the targeted grid. For lean carcass yield grids, emphasize bulls with high ribeye area and low yield grade EPDs. For carcass quality, choose bulls with superior marbling score EPDs. In both cases, target superior EPDs for growth and carcass weight, but avoid upper extremes if cow size is large to prevent heavy carcasses. If you do not intend to retain any heifers for breeding, there s no need to select for traits like milk and calving ease maternal. Putting It All Together Selecting the right bull depends on your breeding objectives, determined by understanding the strengths and weaknesses of your cow herd and the goals for your next calf crop. The best bull for one producer may not be the best for another. The more information you use in bull selection, the fewer surprises. It is important to use both performance information and visual appraisal in choosing a breeding bull. If you select solely on performance numbers, you may inadvertently choose structurally unsound or infertile bulls that will do little for calf crop percentage and herd improvement. On the other hand, if you select bulls based only on visual appraisal, you will almost certainly overlook bulls with genetics more appropriate to your situation.

13 A Successful Performance Program In order to do a better job of serving commercial customers, Limousin breeders must continue to make a priority out of producing cattle with documented quality and predictability. This can be accomplished by appropriately adapting and using both existing and new technologies. The following thoughts are provided as items to consider when developing a more comprehensive performance program for your herd. * Evaluate animals in contemporary groups. A contemporary group is a group of Limousin cattle of the same sex and percentage blood category, born within 90 days of one another, which were managed together. Contemporary groups should always be designated through use of the creep vs. no creep codes and breeder management codes when submitting performance data in order for the data to contribute to calculation of EPDs. Obtaining valid comparisons between animals in groups is essential to formulating reliable EPDs. * In order to ensure that animals are evaluated in contemporary groups, develop a reproductive management program that includes planned and controlled breeding season(s) of 90 days or less. This will help identify reproductively inferior cows so that they can be eliminated from the herd. This also makes it easier to manage the cows from a nutritional standpoint. Restricting the length of the breeding season(s) may be especially important in small herds where it is often difficult to get many animals in the same contemporary group. * Make * Ideally, * Routinely * Consider your records count by planning ahead. All calves in a weaning group should be weighed and evaluated on the same day, when the youngest calf is at least 160 days old and the oldest calf is not over 250 days of age. Yearling weights and other yearling information must be taken at least 140 days after weaning and when the animals are between 330 and 450 days of age. Use the date calculation wheel and instructions provided in your NALF Members Manual. If there is a 90-day age range among cattle in a given group, there is only one possible weaning date to collect data in order for all animals to remain in a contemporary group. data should be reported after each phase of production after calving, following weaning and after processing yearlings. Timely reporting of performance data contributes to more accurate EPDs for all Limousin breeders. update your herd inventory using NALF s online inventory management tool to record reasons why animals leave the herd. Reports from NALF regarding average EPDs for your herd will be more meaningful if your inventory information is up to date. collecting data on additional traits. Genetic documentation of traits such as scrotal circumference, mature cow weight and condition, pelvic dimensions, disposition, and ultrasound ribeye area, rib fat and percent intramuscular fat will help position the Limousin breed to stay ahead of the competition in the years ahead NALF North American Limousin Foundation 7383 S. Alton Way, Suite 100 Centennial, CO / FAX 303/ Canadian Limousin Association #13, th St. NE Calgary, Alberta, Canada T2E 7C4 403/ FAX 403/

14 Reading the Sire Summary Registration # Name Registration # Name Sire Sire CED EPD BW EPD WW EPD YW EPD MA EPD CEM EPD SC EPD ST EPD DOC EPD CW EPD REA EPD YG EPD MARB EPD $SMTI Owner Owner Maternal GrandsireMaternal Grandsire ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC Birthdate Birthdate (# Grps.) (# Dtrs.) (# Sons) B U L L A B U L L B NPM-00000A BIG BULL PAPA BULL B LAND O BOVINES INC. OLD MAN BULL 02/03/98 MIDDLONOWHERE, CO NPM-00000B MR. PRESIDENT HENRY THE EIGHTH P*PN STRETCH LIMO CO. HENRY THE SEVENTH 02/06/95 MOOLINE, IL (2) (37) (10) (50) (205) (25) Animal s registration number. The three letter prefix of the registration number identifies the percentage blood classification. See your NALF Member s Manual for a complete description. Letter codes below the registration number designate polled (P) or scurred (S) status, black color (B) and protoporphyria genotype (*PN = Normal, *PC = Carrier, *PP = Normal based on pedigree, *PS = Proto carrier suspect based on pedigree). Official registered name of animal along with name and current address of owner. Sires in the general listing are printed in alphabetical order. Official name of the sire and maternal grandsire of the animal. CED Calving Ease Direct EPD and accuracy. When sires A and B are bred to similar replacement heifers, you d expect 5 percent (the difference between +10% and +5%) more of sire A s calves to be born unassisted as compared to sire B s calves. Said another way, due to genes for calving ease passed on 5 6 from the sires to their calves, each of sire A s calves out of first-calf heifers have a 5 percent greater chance of being born unassisted as compared to sire B s calves. BW Birth Weight EPD, accuracy and number of contemporary groups (in parentheses) from which progeny birth weights were reported that contributed to the EPD. When mated to equal dams, progeny of sire A (listed above) are expected to weigh 4.0 lbs. less at birth than progeny of sire B ( ), due to genes for birth weight passed on from the sires. WW Weaning Weight EPD and accuracy. Weaning weight EPDs are predictors of pre-weaning growth of progeny. Of the two sires represented above, progeny of sire A are expected to weigh 6 lbs. less than progeny of sire B (44-38) at 205 days of age (when bred to dams of equal value), due to genes inherited for pre-weaning growth from the sires. 7 8 YW Yearling Weight EPD and accuracy. Yearling weight EPDs are predictors of progeny growth to yearling ages. For example, progeny of sire A are expected to weigh 20 lbs. less (92-72) than progeny of sire B at 365 days of age (when mated to equal dams), due to genes for growth from the sires. MA Milking Ability EPD, accuracy and number of daughters with progeny weaning weight records. Milk EPDs are predictors of pounds of daughters progeny weaning weight due to genes for milk the daughters inherit from the parent in question. For example, daughters of sire A are expected to wean calves which are 7 lbs. heavier than calves from daughters of sire B (30-23 lbs.), due to genes for milk passed on to daughters. The milk EPDs of sires A and B were based on 37 and 205 respective daughters with progeny weaning weights CEM Calving Ease Maternal EPD and accuracy. When daughters of sires A and B are bred to similar bulls, daughters of sire A have a 4 percent (14% 10%) greater chance of calving unassisted with their first calf as compared to daughters of sire B, due to differences in genes the daughters inherited from their sires for easy delivery of their first calves. SC Scrotal Circumference EPD, accuracy and number of sons with scrotal measurements which have contributed to the EPD. Scrotal EPDs are expressed in centimeters (cm), with higher values indicating the expectation of genes for larger average yearling scrotal circumferences to be passed on to sons. If mated to equal dams, sire B would be expected to produce sons which average 1.0 cm larger (1.0 0) than the average of sons of sire A. In the above example, measurements from 25 sons contributed to the EPD and the accuracy of.70 for sire B, while 10 sons with measurements were reported from sire A.

15 Reading the Sire Summary Registration # Name Registration # Name Sire Sire CED EPD BW EPD WW EPD YW EPD MA EPD CEM EPD SC EPD ST EPD DOC EPD CW EPD REA EPD YG EPD MARB EPD $SMTI Owner Owner Maternal GrandsireMaternal Grandsire ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC ACC Birthdate Birthdate (# Grps.) (# Dtrs.) (# Sons) B U L L A B U L L B NPM-00000A BIG BULL PAPA BULL B LAND O BOVINES INC. OLD MAN BULL 02/03/98 MIDDLONOWHERE, CO NPM-00000B MR. PRESIDENT HENRY THE EIGHTH P*PN STRETCH LIMO CO. HENRY THE SEVENTH 02/06/95 MOOLINE, IL (2) (37) (10) (50) (205) (25) ST Stayability EPD and accuracy. Stayability EPDs predict genetic differences in the probability that daughters will produce calves at the age of six years or beyond, given that at least one calf was produced prior to the age of six. Generally, higher stayability EPDs represent genetics for greater longevity. Sire B above is expected to have 15% more daughters still in production at the age of six or beyond (+20% vs. +5% = 15% difference) as compared to the percentage of daughters of sire A. Accuracy values indicate the amount of information from daughters which has contributed to the EPDs. DOC Docility EPD and accuracy. Docility EPDs predict genetic differences in the probability that offspring are scored as 1 (docile) or 2 (restless) as opposed to 3, 4, 5 or 6 (nervous to very aggressive). The higher docility EPD for sire A above is preferred to that of sire B; specifically indicating that 25% more (+15% for sire A to -10% for sire B = 25% difference) of sire A s offspring are expected to have scores of 1 or 2 as compared to offspring of sire B. Generally, the higher the accuracy value, the more progeny with docility scores in groups which have contributed to the EPD, making the EPD more reliable and less subject to change. CW Carcass Weight EPD and accuracy. Carcass weight EPDs are used to genetically design carcasses with weights that fall within an acceptable industry weight range. Optimum carcass weight EPDs for sires will vary according to the types of cows to which the sires are mated and the calf growing/finishing management regime. If mated to cows of equal value, sire A would be expected to produce progeny with carcasses 10 pounds heavier (20 10) at harvest than sire B. REA Ribeye Area EPD and accuracy. Ribeye area EPDs offer an objective measurement of genetic differences in muscularity. EPDs for ribeye area are expressed in units of square inches, with larger values indicating larger ribeye area and increased expected overall carcass muscularity. Sire A is expected to produce progeny with ribeye areas that are.30 square inches larger ( ) on average than progeny of sire B. YG Yield Grade EPD and accuracy. Just as lower carcass yield grades are favored and indicate greater cutability, lower YG EPDs are favored and indicate genetic differences for yield grade and cutability of offspring. When bred to similar cows, offspring of sire A are expected to average.10 (.10-0) units of yield grade lower than offspring of sire B. MARB Marbling Score EPD and accuracy. The marbling score EPD is expressed in units of numeric USDA marbling score, with higher values indicating genes for greater deposition of intramuscular fat, or higher expected marbling score and USDA quality grade at a constant age. When mated to similar sets of cows, sire A would be expected to produce progeny with average marbling scores.20 units lower ( ) than sire B. 17 $MTI Mainstream Terminal Index. The mainstream terminal index takes both genetics and economics into account to rank animals in terms of expected profit per carcass produced from weaning to mainstream market endpoints of yield grade 1s and 2s and Select to low-choice quality grades. It is based on the assumption that Angus-Hereford cows in a twobreed rotation are mated to Limousin-influenced terminal sires and is determined primarily by genetics and economics associated with post-weaning growth and yield and quality grade. In this example, if sire A and sire B were mated to similar sets of black baldy cows, sire A would produce progeny with carcasses worth $15 ($55 - $40) more than those of sire B. The mainstream terminal index does not have an associated accuracy value. Trait Leader Designation. Minimum EPDs and accuracy required for trait leader status are listed in the qualifications section.

16 Qualifications General Sire Listing To be included in the general sire listing of the Spring 2010 International Limousin Genetic Evaluation Manual for the U.S. and Canada, the following criteria are required: 1. sired at least one progeny born on or after January 1, possess birth weight and weaning weight EPDs with an accuracy of.50 or greater Please note that as long as the above criteria are met, all other available EPDs are listed regardless of accuracy. Complete EPDs on other Limousin cattle such as older bulls, cows and young animals are available from NALF and the CLA. Proven Sire Trait Leaders In order to be recognized as trait leaders, sires are required to achieve: 1. the requirements listed above for the general listing 2. an accuracy of.50 or higher for the trait in which leader status is designated except the mainstream terminal index, for which all component traits must have an accuracy of.50 or higher 3. rank in approximately the top 75 sires for the trait of interest except stayability, where sires must rank in about the top 25 (due to less data for this trait) In order to be listed as a trait leader in a specific trait, sires must meet or exceed the following level of EPD for that trait: Calving Ease Direct 14 Birth Weight 1.3 Weaning Weight 58 Yearling Weight 92 Milking Ability 25 Calving Ease Maternal 9 Scrotal Circumference.8 Stayability 21 Docility 24 Carcass Weight 31 Ribeye Area.72 Yield Grade.21 Marbling Score.03 Mainstream Terminal Index 46 Due to genetic trend, the requirements for proven sire trait leader designation are likely to change in future evaluations. Young Sire Trait Leaders The listings for young sire prospects recognize the highest ranking yearling and two-year-old bulls in each trait which meet the following qualifications: 1. registered bulls born on or after July 1, 2007 (T, U or W birth code years) 2. non-embryo transplant (ET) produced bulls must have numeric accuracies for birth, weaning and yearling weight EPDs if born in 2007 or 2008 and for birth and weaning weight EPDs if born in bulls produced via ET must have birth, weaning and yearling weights on file if born in 2007 or 2008 and have birth and weaning weights if born in 2009 and their sire and dam or sire and maternal grandsire must have EPDs with 2010 NALF North American Limousin Foundation 7383 S. Alton Way, Suite 100 Centennial, CO / FAX 303/ Canadian Limousin Association #13, th St. NE Calgary, Alberta, Canada T2E 7C4 403/ FAX 403/

17 Q u a l i f i c a t i o n s 2 numeric accuracy in order to compute pedigree based EPDs with P accuracy for these bulls 4. for both ET and non-et produced bulls, scrotal circumference (SC) trait leaders are required to have SC measurements on file and, for non-et produced bulls, be evaluated in valid yearling groups 5. for stayability, have a sire and dam or sire and maternal grandsire with stayability EPDs possessing numeric accuracy 6. for non-et produced bulls, docility (DOC) trait leaders are required to have docility scores reported in qualifying weaning groups (as indicated by docility EPDs with numeric accuracy) and, for ET bulls, have docility scores on file and a sire and dam or sire and maternal grandsire with docility EPDs possessing numeric accuracy 7. rank in approximately the top 100 young sires for the trait of interest In order to be listed as a trait leader in a specific trait, young sire prospects must meet or exceed the following level of EPD for that trait: Calving Ease Direct 22 Birth Weight 4.0 Weaning Weight 68 Yearling Weight 119 Milking Ability 37 Calving Ease Maternal 13 Scrotal Circumference 1.2 Stayability 22 Docility 34 Carcass Weight 55 Ribeye Area.89 Yield Grade.24 Marbling Score.44 Mainstream Terminal Index 60 Dam Trait Leaders In order to be included in the dam trait leader lists, dams are required to meet the following qualifications: 1. active status (e.g., not listed as dead) 2. have a 2008, 2009 or 2010 born progeny 3. possess a minimum accuracy of.30 in order to qualify for the birth, weaning, yearling and milk trait leader lists and minimum accuracy of.25 for the calving ease direct and maternal, scrotal circumference, stayability and docility trait leader lists 4. rank in approximately the top 100 dams for the trait of interest except stayability, where dams must rank in about the top 25 (due to less data for this trait) In order to be listed as a trait leader in a specific trait, dams must meet or exceed the following level of EPD for that trait: Calving Ease Direct 21 Birth Weight 3.4 Weaning Weight 63 Yearling Weight 93 Milking Ability 39 Calving Ease Maternal 13 Scrotal Circumference.8 Stayability 20 Docility 33 Carcass Weight 46 Ribeye Area.95 Yield Grade.32 Marbling Score.41 Mainstream Terminal Index 52 Due to genetic trend, the requirements for dam trait leader designation are likely to change in future evaluations. Due to genetic trend, the requirements for young sire trait leader designation are likely to change in future evaluations.

18 Spring 2010 EPD Statistics and Trends SPRING 2010 EPD STATISTICS CURRENT SIRES OF BORN CALVES CE Birth Weaning Yearling Milking CE Scrotal Carcass Ribeye Yield Marbling Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI Number of Sires 2,869 2,878 2,878 2,878 2,888 2,869 2,790 1,252 2,451 2,438 2,438 2,438 2,438 2,438 Average EPD Standard Deviation Min EPD Max EPD CURRENT DAMS OF BORN CALVES CE Birth Weaning Yearling Milking CE Scrotal Carcass Ribeye Yield Marbling Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI Number of Dams 27,774 27,969 27,969 27,969 28,063 27,774 26,882 15,052 21,928 21,367 21,367 21,367 21,367 21,365 Average EPD Standard Deviation Min EPD Max EPD BORN CALVES CE Birth Weaning Yearling Milking CE Scrotal Carcass Ribeye Yield Marbling Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI Number of Calves 38,556 39,327 39,326 39,326 39,783 38,556 33,523 1,611 23,135 27,611 27,611 27,611 27,611 27,547 Average EPD Standard Deviation Min EPD Max EPD BORN LIM-FLEX CALVES CE Birth Weaning Yearling Milking CE Scrotal Carcass Ribeye Yield Marbling Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI Number of Calves 7,118 7,417 7,417 7,417 7,496 7,118 4, ,961 6,716 6,716 6,716 6,716 6,675 Average EPD Standard Deviation Min EPD Max EPD NALF North American Limousin Foundation 7383 S. Alton Way, Suite 100 Centennial, CO / FAX 303/ Canadian Limousin Association #13, th St. NE Calgary, Alberta, Canada T2E 7C4 403/ FAX 403/

19 S p r i n g E P D S t a t i s t i c s a n d T r e n d s 2 PERCENTILE BREAKDOWN CURRENT SIRES OF BORN CALVES Upper Calving Calving Percentile Ease Birth Weaning Yearling Milking Ease Scrotal Carcass Ribeye Yield Marbling Group Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI 1% % % % % % % % % % % % % % PERCENTILE BREAKDOWN CURRENT DAMS OF BORN CALVES Upper Calving Calving Percentile Ease Birth Weaning Yearling Milking Ease Scrotal Carcass Ribeye Yield Marbling Group Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI 1% % % % % % % % % % % % % % PERCENTILE BREAKDOWN BORN CALVES Upper Calving Calving Percentile Ease Birth Weaning Yearling Milking Ease Scrotal Carcass Ribeye Yield Marbling Group Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI 1% % % % % % % % % % % % % % LIM-FLEX CALVES FOLLOW ON NEXT PAGE

20 S p r i n g E P D S t a t i s t i c s a n d T r e n d s 3 PERCENTILE BREAKDOWN BORN LIM-FLEX CALVES Upper Calving Calving Percentile Ease Birth Weaning Yearling Milking Ease Scrotal Carcass Ribeye Yield Marbling Group Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI 1% % % % % % % % % % % % % % Limousin Genetic Trends Average EPDs by Birth Year, Calving Ease Birth Weaning Yearling Milking Calving Ease Scrotal Carcass Ribeye Yield Marbling Year Direct Weight Weight Weight Ability Maternal Circum. Stayability Docility Weight Area Grade Score $MTI

21 S p r i n g E P D S t a t i s t i c s a n d T r e n d s 4 Limousin Genetic Trends Growth Traits YEARLING WEIGHT S T A N D A R D D E V I A T I O N U N I T S MILKING ABILITY WEANING WEIGHT BIRTH WEIGHT S T A N D A R D D E V I A T I O N U N I T S Limousin Genetic Trends Reproductive Traits and Docility CALVING EASE MATERNAL CALVING EASE DIRECT STAYABILITY SCROTAL CIRCUMFERENCE DOCILITY S T A N D A R D D E V I A T I O N U N I T S Limousin Genetic Trends Carcass Traits and $MTI RIBEYE AREA CARCASS WEIGHT MAINSTREAM TERMINAL INDEX MARBLING SCORE YIELD GRADE Standard Units = Mean EPD for each trait by year divided by the overall standard deviation of the EPDs for the trait.

22 Spring 2010 General Sire Listing NORTH AMERICAN LIMOUSIN FOUNDATION